Distributed solar reduced New England wholesale power costs by nearly $20 million dollars during a heat wave from July 1 to July 7, according to a new analysis completed by Synapse Energy Economics.

During peak hours for electricity demand, distributed solar can reduce load on the New England grid by more than 1 GW, the report found, helping to reduce system-wide costs. The analysis was commissioned by SunCommon, a distributed solar provider.

Earlier this year ISO-New England said it expects to see declining energy use and peak load over the next decade, largely due to efficiency and behind-the-meter solar. The analysis found solar is expected to produce 2,162 GWh of total annual energy savings in 2018, rising to almost 4,800 GWh in 2027.

Renewable energy advocates have long touted the system-wide benefits of distributed solar, and Synapse’s research adds a new data point to the argument.

SunCommon officials said they knew solar contributes “in a big way” to the system during heatwaves, but “wanted to put numbers to it,” co-founder James Moore said in a statement.

The report says the amount of solar produced during the week-long July heatwave was the equivalent of removing 1.37 million homes from the grid.

According to the analysis, states with higher load and more distributed solar experienced greater wholesale cost savings than states with less solar and lower power demand.

SunCommon says Massachusetts holds about half of New England’s solar capacity, and contributed $9.3 million in savings from solar during the period analyzed.

New England solar power has increased times 60 between 2010 and 2017, the Synapse report notes….